The present invention relates to a dental implant device for reconstructing teeth.
In tooth reconstruction, the implantation technique is becoming more and more important. In assessing the proposals that have been disclosed, one finds that the technical orientation over the years has not substantially changed. In a chronological outline the relevant printed references, one finds that the known implants are always based on a supporting device designed in various different ways, which is incorporated into the jawbone in various ways and which substantially comprises an abutment portion fixed in various ways to the supporting device. The external shape of the abutment portion then forms the seat or support for the reconstructed tooth. These implant parts, which in the prior art are made of titanium or a titanium alloy, have many different shapes, and many different types of connections have been proposed between the supporting device and the abutment portion. The following significant references in the prior art are an indication of the manifold nature of the proposals that have been disclosed. Among many others, the following can be named:
U.S. Pat. Nos. 4,854,872; 4,872,839; 5,082,442; 5,152,687; and European Patent Disclosure No. EP-A1-0 477 644.
In none of the proposals listed above can fundamental problems of the implantation technique be solved. The tooth configuration of every person differs in shape, geometric extent, and position in the dental arch, which is why, in the implants that have been disclosed, a difficult adaptation must always be made in the region of the receiving seat of the abutment portion in the gums if the individual reconstructed tooth deviates from the plane defined by the supporting device and the abutment portion, or, if the dimensions of the root, which are predetermined by the supporting device, should change. It is found that the available commercial selection leaves little room for maneuvering in terms of making the desired adaptations at little effort or expense. For instance, this difficult adaptation may comprise machining the portion of the abutment toward the gum, which abutment acts as a receiving seat for the tooth to be reconstructed, in such a way that a suitable correction in terms of position and shape thereof results. It is evident that performing such machining in the installed state makes major demands on the practitioner both visually and in terms of manual skill. Even a small deviation in machining has an immediate adverse effect on the end product. Corrections to that end are always complicated and not infrequently proved to be merely patch work.
The same is true for the proposals according to U.S. Pat. Nos. 5,040,983; 5,106,300; and 5,135,395, which are distinguished by an especially complex structure between the supporting device and the abutment portion.
Essentially two fundamental problems fail to be solved satisfactorily by any of the above-listed proposals. First, it is demonstrated that if there is even the slightest retraction of the gum, the abutment area becomes visible. This is always apparent from a dark linear curve above the border of the gum (i.e., above the gum line), which always means a perceptible impairment of the aesthetic appearance, leaving something to be desired in terms of acceptance of the disclosed concepts. In seeking a reliable remedy for this, the transition between the supporting device and the abutment portion would have to be shifted to an area deep in the gum, but this is only possible if enough gum is still present. Second, the gap that unavoidably forms at the transition between the supporting device and the abutment portion and at the transition between the abutment portion and the implant proves to be extremely vulnerable to bacterial colonization, which increases the risk of extremely rapid dramatic gum loss and thus completely reverses the success of the reconstruction.
Conversely, in German Patent Disclosure DE-A1-42 30 009, a proposal has been disclosed that is capable of remedying substantial disadvantages of the prior art disclosed prior to it. The disclosed technique can be seen as an improvement since every reconstruction is based on an individual or standardized abutment, which can then be prepared to make an individualized retaining mold for the reconstructed tooth. The abutment itself comprises a metal core, with a sheath made of ceramic, a plastic, or composite material. The preferably plastic sheath extends deep into the anchoring region of the abutment, in such a way that even if there is a drastic gum loss, the metal terminal core of the abutment, or the supporting device, should not become visible, thus surely considerably enhancing the acceptance of this proposal compared to the prior art disclosed prior to it. However, an aspect of this proposal that can be emphasized as still unsatisfactory is the transition, located deep in the gum, between the metal supporting device and the abutment. This transition, however perfectly achieved, always forms a gap bacteriologically, and as a result, there is an intrinsic vulnerability to bacterial colonization. A gap shifted as deep as possible into the gum for aesthetic reasons can be reached by conventional cleaning means only with great difficulty. The resultant bacteriological problems are notorious in dentistry.
The object of the present invention is to provide an improved dental implant technique in which all of the disadvantages, with individual or multiple effect, of the implants of the prior art are overcome.
Fundamentally, the present invention proposes integrating or fusing the supporting element and abutment portion into a single unit. This single unit performs the function of a substructure. The lower region of the substructure serves as a supporting element, and the upper region of the substructure takes on all the functions of a technologically highly placed abutment portion.
According to the present invention a dental implant device for reconstructing teeth comprises a supporting element adapted to be solidly connected in a jawbone and ending in a gingival region; and an abutment portion extending from the supporting element and extending above the gingival region, which abutment portion serves as a receiving seat for a tooth crown of a tooth to be reconstructed. The supporting element and the abutment portion form a single unitary substructure or a multipart substructure. The single unitary substructure comprises an inner metal core and an outer sheath surrounding the inner metal core, the outer sheath being made of a ceramic and/or a composite material having substantially the same color as the tooth crown of the tooth to be reconstructed.
Exemplary embodiments of the invention will be described in detail below. Any elements not necessary for immediate comprehension of the invention have been left out. In the various drawing figures, identical elements are identified by the same reference numerals.